Gallbladder abnormalities associated with hypoplasia of the right lobe of the liver.

PURPOSE: We investigated the gallbladder abnormalities associated with anomalous right hepatic lobes using US, CT, and/or MRI. MATERIALS AND METHODS: The patients, four men and four women, ranged in age from 15 to 91 years, with a mean age of 59.5 years. The right lobe was hypoplastic in seven patients and was completely absent in one patient. RESULTS: The gallbladder was normally positioned in two patients (infrahepatic) and was absent in two patients. The gallbladder was located posterior to the liver in one patient (retrohepatic) and was located below the right hemidiaphragm in two patients (suprahepatic). Gallstones were present in one patient with jaundice and epigastralgia. CONCLUSION: Anomalous position or agenesis of the gallbladder often accompanies hypoplasia of the right hepatic lobe. Gallbladder position could be a good indicator of right hepatic lobe anomaly.

Intrahepatic portal-hepatic venous shunts demonstrated by US, CT, and MR imaging.

PURPOSE: Radiological findings were investigated in 6 cases of intrahepatic portal-hepatic venous shunt (IPHVS) without chronic liver disease. MATERIAL AND METHODS: Six patients with IPHVS were examined using US, CT and MR imaging. US was performed in all patients and color Doppler imaging in 5 patients. CT was performed after i.v. bolus injection of contrast medium in 4 patients. MR imaging and MR angiography were performed in one patient. RESULTS: The shunt was present in the right lobe in 4 patients and in the left lobe in 2 patients. The shunts consisted of focally dilated or tubular vessels (1 aneurysmal) in 4 patients, and multiple small vessels in 2 patients. US revealed anechoic structures with various configurations at the shunt. Color Doppler imaging could detect blood flow in various directions in the shunt vessels in 5 patients. CT and MR images showed these abnormal vascular structures in the liver. MR angiography was also useful for evaluating the relationship between the portal and the hepatic veins. CONCLUSION: Color Doppler imaging was the best modality for evaluation of IPHVS.

Motion related artifacts in spin-echo MR imaging: effects of sequence parameters on image quality at 1.5 Tesla.

PURPOSE: The purpose of this study was to evaluate the effects of selected parameters in a conventional spin-echo MRI sequence on image quality in a phantom undergoing periodic motion. METHODS: Images of a composite oil/copper sulfate phantom moving in a 1.5 Tesla magnet were acquired. The CuSO4 ghost signal-to-noise ratio (SNR) and distances between corresponding points on the phantom image and adjacent ghosts were evaluated. RESULTS: Increasing time to repeat (TR) and number of acquisitions (NAq) improved image quality. Ghost SNR was near unity at TR = 500 msec and at NAq around 4. Increasing TR and NAq resulted in increased distance between images. The effects of field of view (FOV) and matrix size on image quality were relatively less significant. CONCLUSION: Increasing NAq appeared to have a comparatively greater effect on ghost SNR and image quality under our experimental conditions. However, the effect of increasing NAq on image quality appeared to be definite since a saturation point was reached after a particular NAq. Increasing NAq above this point resulted in a relatively smaller improvement in image quality.

Epithelial cyst of the gallbladder demonstrated by ultrasonography: case report.

We present a rare case of epithelial cyst of the gallbladder in a 71-year-old man. Abdominal ultrasonography revealed a small cystic structure adjacent to the gallbladder. The cyst wall was thin and smooth, and protruded into the lumen of the gallbladder. Histologically, the cyst had no communication with the lumen of the gallbladder. The cyst wall was composed of fibro-muscular fiber, and lined by a single layer of ciliated columnar epithelium. Epithelial cyst of the gallbladder should be included in the differential diagnosis when radiological studies show a cystic structure in or adjacent to the gallbladder.

Hypoplasia of the right hepatic lobe with ectopy of the gallbladder.

Two cases of hypoplasia of the right hepatic lobe with gallbladder ectopy, which were diagnosed by computed tomography, are reported here. In each patient, the left hepatic lobe was enlarged. The gallbladder was located in the inferior portion of the liver in one patient and immediately below the right hemidiaphragm in the other. No other anomalies complicated these two cases. It should be kept in mind that hepatic lobe anomalies may have associated ectopy of the gallbladder.

Discovertebral junction of the spine--a cadaveric study by spin-echo MR imaging.

To evaluate the MR appearance of the discovertebral junction (DVJ) of the spine, we examined 161 DVJs in 27 cadaveric spines using superconductive MR imaging. T1-, proton density-, and T2-weighted spin-echo imaging were used. With a small surface coil, higher resolution and more sharply defined contours of the DVJ were obtained than when using a head coil. Cortical bone had very low signal intensity in all sequences. Cartilaginous end-plate (CP) was of low to intermediate signal intensity on T1-weighted images, and of low signal intensity on proton density- and T2-weighted images. MR images were able to reveal the gross CP appearances, Schmorl's nodules, and adjacent bone marrow pathology. We conclude that MR imaging is valuable for assessing abnormalities of the DVJ.

Contrast-enhanced MR imaging of intrahepatic cholangiocarcinoma.

The unenhanced spin-echo T1-weighted images, contrast-enhanced (dynamic and conventional) T1-weighted images and spin-echo T2-weighted images of 19 patients with histologically proven intrahepatic cholangiocarcinoma were reviewed. The results showed that typical intrahepatic cholangiocarcinoma presented as a large mass of low signal intensity on T1-weighted images. On T2-weighted images tumours generally presented as high signal intensity masses. In five patients the tumours exhibited varying degrees of central hypointensity on T2-weighted images. On contrast-enhanced images, large tumours (diameter larger than 4 cm, n = 14) typically showed peripheral enhancement with delayed or incomplete central filling. This pattern was seen most commonly. Smaller tumours (diam. 2-4 cm, n = 5) typically exhibited homogenous enhancement. On dynamic studies, enhancement of the tumours showed a centripetal pattern. Complete enhancement was observed in the small tumours. Among the larger lesions central sparing of the tumours was seen. It is concluded that contrast-enhanced MR imaging is useful in the diagnosis of intrahepatic cholangiocarcinoma. The characteristic enhancing pattern of intrahepatic cholangiocarcinoma was seen less commonly in smaller tumours. Definite differentiation from other liver masses in this case could be less certain.

Intraspinal gas associated with intestinal necrosis detected by CT.

We report the case of a 63-year-old woman with necrosis of the small intestine and intraspinal collections of gas, which were detected using computed tomography (CT). Abdominal CT revealed extensive collections of gas in the portal and mesenteric veins and within the intestinal walls. Gas radiolucencies were also noted in the epidural spaces of her spine. This gas was considered to have migrated from the pelvic venous system into the internal venous plexus of the spine. Intestinal necrosis should be included in the differential diagnosis of intraspinal gas collections during CT.

CT manifestations of intraspinal air associated with pneumomediastinum.

Collections of air in the spinal canal have been observed in patients with spinal disorders, whereas intraspinal air secondary to pneumomediastinum is rare (6). This is a report of 2 patients with pneumomediastinum where collections of air were identified in the spinal canal on CT.

Neurofibromatosis type 1 involving the liver: ultrasound and CT manifestations.

We present a rare case of neurofibromatosis type 1 (NF-1) involving the liver in a 15-year-old girl. Abdominal ultrasonography revealed infiltrative hypoechoic masses around the porta hepatitis and intrahepatic portal branches. CT also revealed extensive low-attenuation masses in the hepatic hilum and retroperitoneum. The tumor spread into the liver along the portal vein. It should be borne in mind that the liver may be involved by neurofibromas in patients with NF-1.

Portocaval shunt with unusual CT and MR manifestations.

OBJECTIVE: We investigated the radiological findings of three cases with unusual portocaval shunts. MATERIALS AND METHODS: Three patients with liver cirrhosis and portal hypertension were examined using CT and MRI. CT was performed using intravenous bolus injection of contrast medium in one and with incremental dynamic scanning in two cases. MRI was performed with a 1.5 or 0.5 T superconducting system or with a 0.22 T resistive system in the three patients. RESULTS: CT and MRI showed tortuous intrahepatic tubular structures connecting the right posterior portal vein to the inferior vena cava (IVC) in two of the patients. An anomalous vein arising from the extrahepatic portal vein was a tributary connected with the IVC in one patient. Symptoms associated with hepatic encephalopathy were present in two of the patients whose blood ammonia levels were elevated. CONCLUSION: The possibility of the existence of hepatic encephalopathy should be borne in mind when these shunts are detected during abdominal imaging.

[Evaluation of lumbar vertebral bone marrow changes with MR imaging].

Seven hundred nine magnetic resonance (MR) imaging studies of the lumbar spine were reviewed to assess the signal intensity (SI) changes in vertebral bone marrow. Marrow changes were classified into four types according to their SI changes on T 1-weighted images (T 1-WI) and T 2-WI. Type 1 changes (decreased SI on T 1-WI and increased SI on T 2-WI) were identified in 28 patients (3.9%), type 2 changes (increased SI on T 1-WI and isointense or slightly increased SI on T 2-WI) in 184 (26%), type 3 changes (decreased SI on both T 1-, T 2-WI) in 71 (10%), and type 4 changes (linearly increased SI on T 1-WI in the center of the vertebral body) in 142 (20%). Plain radiographs showed sclerotic changes in patients with type 3. In patients with type 1 or 4 changes, no focal abnormalities were observed. Histological evaluation of type 1 change revealed fibrous tissue including cartilaginous formation. Focal replacement by fatty tissue was observed in type 2 and type 4 changes. Bone sclerosis was observed in type 4 change. Type 1, type 2 and type 3 changes, which occurred commonly in the old and in the lower lumbar levels, appear to reflect a spectrum of degenerative changes of the bone marrow including both pathological and physiological ones.

Optimal timing for delineation of hepatocellular carcinoma in dynamic CT.

OBJECTIVE: The aim of our study was to ascertain the optimal timing and scanning method for detecting hepatocellular carcinoma (HCC) as a high density mass during the early phase of dynamic hepatic CT and to confirm its clinical effectiveness. MATERIALS AND METHODS: We studied retrospectively 39 patients with clinically diagnosed HCC who underwent dynamic hepatic CT. RESULTS: All nine lesions that were scanned within 60 s after initiating injections were detected as high density masses. However, 15 of 21 lesions (71%) that were scanned > 70 s after initiating injections could not be detected as high density masses. Using helical scanning, which permitted scanning the entire liver within 60 s after initiating injections, 27 of 31 lesions (87%) were detected as high density masses. CONCLUSION: We concluded that most HCCs can be detected as high density masses during the early phase of dynamic CT using helical scanning.

Repositioning of a displaced catheter for percutaneous hepatic arterial infusion chemotherapy.

This is a report of a patient with hepatocellular carcinoma whose hepatic arterial catheter, which was introduced via a subclavian arterial branch, migrated into his right gastric artery. The catheter was successfully maneuvered to a suitable position without any further invasive procedure. The importance of preparatory embolization of the right gastric artery is underscored.

CT manifestations of lipomas of the small intestine and colon.

Seven cases of lipoma of the intestine demonstrated by computed tomography (CT) are reported. There were three men and four women who ranged in age from 47 to 78 years. The lipomas were in the small intestine in four patients, and in the colon in three. CT documented the characteristic low attenuation (fat density) of these masses in all patients. It is concluded that intestinal lipomas are important indications for CT evaluations.

Retroperitoneal leiomyosarcoma. Its MR manifestations.

The magnetic resonance manifestations of retroperitoneal leiomyosarcomas in two patients are described. The tumors were isointense to muscle on T1-weighted images and exhibited a relatively high signal on T2-weighted images. Postcontrast T1-weighted images after the administration of gadolinium-dietilenetriaminepentaacetic acid produced moderate enhancement except in regions of central necrosis.

CT and MRI manifestations of intraabdominal panniculitis.

We report a case of intraabdominal panniculitis. Computed tomography (CT) showed diffuse increased attenuation in the omentum, mesentery, and retroperitoneal region. As the disease progressed, the entire mesentery and retroperitoneal regions were involved. On magnetic resonance imaging (MRI), the lesion demonstrated an intermediate signal intensity on T1-weighted images and a slightly high signal intensity on T2-weighted images. Though the radiologic findings are not specific, this condition should be considered in the appropriate clinical context.

MR imaging of anomalous lobes of the liver.

Four patients with anomalous lobes of the liver were observed at MR imaging. In one patient the anterior segment of the right hepatic lobe was absent and in 3 patients the left hepatic lobe was anomalous. The hepatic vasculature supporting the information of the anomalous hepatic lobes was well observed in all patients.

Pelvic kidney associated with other congenital anomalies: US and CT manifestations.

Two cases of pelvic kidney with other associated congenital anomalies were demonstrated using ultrasonography (US) and computed tomography (CT). Urogenital anomalies are not uncommon, but Riedel's hepatic lobe is a rare anomaly in patients with pelvic kidneys.

Hepatocellular carcinoma invading the gallbladder: CT, arteriography and MRI findings.

Hepatocellular carcinoma (HCC) seldom invades the gallbladder. We report a case of HCC invading the gallbladder that resembled gallbladder carcinoma invading the liver. The diagnosis was confirmed by surgical biopsy. The arteriographic, computed tomography and magnetic resonance imaging findings are presented.